Rotator cuff disease impacts over 50% of the population over age 60, with a range of severity from partial thickness through total rupture. This disease is believed to be degenerative and will continue to worsen if there is no intervention. It is currently believed that the transition from type I to type II collagen in the tendenous tissue may contribute to rotator cuff disease. In current clinical practice, treatment decisions are frequently made through subjective assessment of pain and range of motion combined with qualitative assessment of X-ray or ultrasound images. Treatment of disease may include physical therapy, surgery, or a combination of both. Patient history, physical examination, and medical imaging are used to determine course of treatment. However, currently there is little objective data upon which to determine disease progression or injury, which can lead to unnecessary, inappropriate, painful, and expensive treatments that may or may not benefit the patient. Indeed, the final determination of the best course of action is typically at the subjective discretion of the clinician, and is often based on personal experiences as opposed to quantitative standards.
Ultrasound can visualize and assess subsurface tissues while posing extremely low risk to the patient and practitioner. Techniques in ultrasound acquisition and post-processing have been used for the non-invasive determination of tissue mechanical properties. This combined process has become known as ultrasound elastography, and has shown much promise in the diagnosis of disease and disorder. See, e.g., Garra et al., Elastography of breast lesions: initial clinical results, Radiology 1997; 202:79-86; Whittaker et al., Rehabilitative ultrasound imaging: understanding the technology and its applications; J Orthop Sports Phys Ther 2007; 37: 434-49; and Cochlin et al., Elastography in the detection of prostatic cancer; Clinical Radiology 2002; 57: 1014-20.
Despite the foregoing, there remains a need for alternate, cost effective and easy-to-use devices and systems that provide objective measurements of tissue elasticity and/or stiffness.